The geometrically nonlinear response of a circular sandwich plate that consists of two
face sheets and a compliant (“soft”) core with mechanical properties that may be
either independent or dependent of temperature and subjected to both mechanical
loads and thermal induced deformations, but remain elastic linear throughout the
loading process, is presented. The mathematical formulation follows the principles of
the high-order sandwich panel theory (HSAPT) and includes the vertical flexibility of
the core in addition to the temperature dependency of the mechanical properties of
the core material. The mathematical formulation outlines the set of governing partial
differential equations as well the appropriate boundary conditions for a general
sandwich layout. The particular case of an axisymmetric circular sandwich
plate subjected to axisymmetric mechanical and thermal loads, and with
axisymmetric boundary conditions is studied analytically and numerically. The
numerical study includes an interaction of mechanical and thermal loads which is
presented through results within the plate for various load levels of various
structural quantities as well as equilibrium curves of temperatures versus these
structural quantities. The results reveal that the combination of mechanical
and thermal loads along with a compliant core material with mechanical
properties that degrade with increasing temperatures shifts the behavior from a
linear and stable (strength controlled) response into a strongly nonlinear
response with limit point behavior and associated loss of stability, when large
displacements and large rotations (geometrical nonlinearity) are included in the
modeling.
Professor, Ashtrom Engineering
Company Chair in Civil Engineering Technion - Israel Institute
of Technology
Faculty of Civil and Environmental Engineering
Haifa, 32000
Israel
